In order to solve the problems of short reference working distance and small measuring range of laser displacement sensors developed independently in China at present, an imaging optical system for a wide-range laser displacement sensor was designed, which was suitable for the long distance measurement. Based on the laser triangulation principle, combined with specific application requirements, the performance indicators of a wide-range laser displacement sensor and parameters of an imaging optical system were calculated. The five-piece lens structure was selected as the initial structure of the system, and the imaging optical system of wide-range laser displacement sensor was designed with optical design software. The optimal design and performance analysis of the system were completed, and the system with reference working distance of 1 000 mm, measuring range of ±500 mm and resolution of 0.4 mm was developed. The simulation results show that the system can achieve good imaging quality within the measuring range of ±500 mm. The proposed laser displacement sensor imaging system has the advantages of long working distance, wide measuring range and simple structure, which can meet the requirements of wide-range measurement at 1 000 mm.